1. Field of the Invention
The invention relates generally to the design of circulation valves and sliding sleeve tools.
2. Description of the Related Art
Wellbore tools have been developed that are operated by a ball or plug that is dropped into the tool and landed on a seat within the tool. The ball or plug serves to increase pressure and/or to redirect fluid flow through the tool in order to operate the tool. Tools of this type include circulation valves which are used to selectively open and close lateral fluid flow ports in a tool sub to permit fluid flowing axially through the tool to be diverted into the surrounding flowbore.
The parent application to this one describes tools that operate by using balls or plugs of different sizes. The parent application to this application is U.S. patent application Ser. No. 13/469,852 filed May 11, 2012, which is incorporated herein by reference in its entirety.